High-frequency filter and electronic device

ABSTRACT

A flat cable high-frequency filter includes a dielectric substrate extending in a transmission direction of a high-frequency signal. The dielectric substrate includes dielectric layers stacked on each other. Elongated conductor patterns are provided on a flat surface of one dielectric layer which faces another dielectric layer. The conductor patterns are as wide as possible in the dielectric substrate in accordance with a desired inductance. A capacitive coupling conductor pattern opposes one conductor pattern by a predetermined area with a dielectric layer therebetween. By using a connecting conductor, the capacitive coupling conductor pattern is connected to the conductor pattern which does not oppose the capacitive coupling conductor pattern.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a flat cable high-frequency filter anda flat cable high-frequency diplexer, each of which is a thin, flat filmand has a frequency selection function, and an electronic deviceincluding the flat cable high-frequency filter or the flat cablehigh-frequency diplexer.

2. Description of the Related Art

Hitherto, an electronic device using high-frequency signals, such as amobile terminal, includes a high-frequency filter for separating ahigh-frequency signal in a desired frequency band from unwantedhigh-frequency signals and harmonic signals.

The structure of a known high-frequency filter is, for example, thestructure disclosed in Japanese Unexamined Patent ApplicationPublication No. 2002-57543. The high-frequency filter disclosed in thispublication is constituted by a mounting multilayer body obtained bystacking a plurality of dielectric layers and by sintering them.Inductors and capacitors forming the high-frequency filter areimplemented by conductor patterns formed within the multilayer body.

In accordance with a reduced size of an electronic device, the mountarea for a high-frequency filter constituted by the above-describedmounting multilayer body is more and more restricted. It is thusdemanded that the size of a high-frequency filter be also reduced. Inthis case, the size and the thickness of conductor patterns formedwithin the multilayer body forming inductors and capacitors are alsodecreased.

However, if the size of a mounting high-frequency filter is reduced, thedevice characteristics of inductors and capacitors are decreased. Forexample, concerning inductors, the equivalent series resistance (ESR) isincreased due to a decrease in the thickness of the inductors.Concerning capacitors, the equivalent series inductance (ESL) isincreased due to a complicated wiring pattern for forming ahigh-frequency filter. Because of the decreased device characteristics,the Q factor of the high-frequency filter is reduced, thus increasingthe loss in the high-frequency filter.

When connecting a high-frequency filter between circuits on a pluralityof mount boards, one of the following structures is employed for theabove-described known mounting high-frequency filter. The high-frequencyfilter is mounted on one mount board and is connected to the other mountboard by using a flat cable. Alternatively, an intermediate mount boardis disposed between two mount boards, and a high-frequency filter ismounted on this intermediate mount board and is connected to the twomount boards by using flat cables.

With the above-described structures, transmission loss occurs in theindividual flat cables, and thus, in addition to the loss in theabove-described high-frequency filter, transmission loss is alsoincurred.

A mounting multilayer body forming a high-frequency filter requires acertain height. Accordingly, a space is required on the mount surface ofa mount board in accordance with the height of the multilayer body.

SUMMARY OF THE INVENTION

Preferred embodiments of the present invention provide a space-savinghigh-frequency filter having small-loss transmission characteristics.

A flat cable high-frequency filter according to a preferred embodimentof the present invention includes a dielectric substrate, a plurality ofconductor patterns, and a capacitive coupling conductor pattern. Thedielectric substrate is a flat film and extends in a transmissiondirection of a high-frequency signal. The plurality of conductorpatterns are provided in the dielectric substrate, extend along anextending direction of the dielectric substrate, and are separated fromeach other at a position between two ends of the extending direction ofthe dielectric substrate. The capacitive coupling conductor patterncapacitively couples the plurality of conductor patterns. In this flatcable high-frequency filter, the plurality of conductor patterns defineinductors, and the capacitive coupling conductor pattern defines acapacitor.

With this configuration, an LC series resonance circuit of inductors anda capacitor is defined by the conductor patterns formed in the flat-filmdielectric substrate. A high-frequency filter is implemented by this LCseries resonance circuit.

In the flat cable high-frequency filter, the dielectric substrate maypreferably have a dielectric loss tangent equal to or smaller than about0.005, for example.

With this configuration, the Q factor of the LC series resonancecircuit, that is, the high-frequency filter, is improved. It is thuspossible to implement a flat cable high-frequency filter exhibitinghigher transmission characteristics.

In the flat cable high-frequency filter, the dielectric substrate maypreferably be made of a liquid crystal polymer.

With this configuration, it is possible to implement a thin dielectricsubstrate having high flexibility while exhibiting a small dielectricloss tangent.

In the flat cable high-frequency filter, a conductor pattern connectedto a ground potential preferably may not be formed in the dielectricsubstrate.

With this configuration, a stray capacitance is not generated between aconductor pattern and a ground, thus obtaining even higher filtercharacteristics and transmission characteristics.

The flat cable high-frequency filter may further include a shieldconductor pattern that is a flat film and that opposes flat filmsurfaces of the plurality of conductor patterns which do not define thecapacitor with a predetermined distance therebetween.

With this configuration, in a region in which the inductor is located,it is possible to significantly reduce or prevent electromagneticinterference of the conductor patterns with the outside. In a region inwhich the capacitor is located, it is possible to obtain a desiredcapacitance with high precision.

In the flat cable high-frequency filter, the shield conductor patternmay preferably be disposed opposing each of both surfaces of a conductorpattern so as to sandwich the conductor pattern therebetween.

With this configuration, interference of the conductor patterns with theoutside is further significantly reduced or prevented.

In the flat cable high-frequency filter, a bent portion may preferablybe located at a position other than a region in which the capacitivecoupling conductor pattern is formed along the transmission direction ofthe dielectric substrate.

In this configuration, even if the flat cable high-frequency filter isbent and disposed, the capacitor forming region is not bent.Accordingly, the capacitance is not changed, and thus, thecharacteristics of the flat cable high-frequency filter are not changed.

In the flat cable high-frequency filter, the capacitive couplingconductor pattern may be constituted by a flat conductor pattern whichis disposed opposing a certain one of the plurality of conductorpatterns with a dielectric layer forming the dielectric substratetherebetween and a flat region of the certain one of the plurality ofconductor patterns which opposes the flat conductor pattern.

In the flat cable high-frequency filter, the capacitive couplingconductor pattern may be constituted by a flat conductor pattern whichis disposed opposing the plurality of conductor patterns with adielectric layer defining the dielectric substrate therebetween and flatregions of the plurality of conductor patterns which oppose the flatconductor pattern.

In the flat cable high-frequency filter, the plurality of conductorpatterns may be provided on different surfaces with a dielectric layerdefining the dielectric substrate therebetween. The capacitive couplingconductor pattern may be constituted by a region by which the pluralityof conductor patterns oppose each other with the dielectric layertherebetween.

In the above-described structures, the specific configuration of thecapacitor forming region is indicated. The capacitance is determined bythe thickness of the dielectric layer and the area of the opposingsurfaces of the conductor patterns parallel with the flat surface of thedielectric layer. With this arrangement, a comparatively highcapacitance is obtained.

In the flat cable high-frequency filter, a width, which is in adirection perpendicular to the transmission direction, of a conductorpattern which opposes the capacitive coupling conductor pattern maypreferably be the same or substantially the same as the width of aconductor pattern which does not oppose the capacitive couplingconductor pattern.

With this configuration, the ESR of the inductor is reduced to a minimallevel. This makes it possible to further improve the band passcharacteristics and the transmission characteristics of thehigh-frequency filter.

In the flat cable high-frequency filter, the widths of the conductorpatterns may preferably be substantially the same as a width of thedielectric substrate.

With this configuration, the ESR is reduced to a minimal level whilemaintaining the environmental resistance of the conductor patterns.

In the flat cable high-frequency filter, the capacitive couplingconductor pattern may be constituted by interdigital conductors whichare integrally provided at opposing end portions of the plurality ofconductor patterns and which oppose each other by a predetermineddistance along the transmission direction.

With this configuration, by the use of a single layer on which theconductor patterns are provided, it is possible to implement ahigh-frequency filter including an LC series resonance circuitconstituted by an inductor and a capacitor. It is thus possible to makethe flat cable high-frequency filter even thinner.

The flat cable high-frequency filter may be configured as follows. Theconductor pattern may be constituted by a first partial conductorpattern and a second partial conductor pattern, one end of the firstpartial conductor pattern and one end of the second partial conductorpattern being connected to each other. The first partial conductorpattern may be wider than the second partial conductor pattern and maybe linearly configured along the transmission direction. The secondpartial conductor pattern may be configured substantially in a loopshape. The first partial conductor pattern may define the capacitor, andthe second partial conductor pattern may define the inductor.

With this configuration, by using a flat cable, a high-frequency filterhaving desired characteristics is implemented.

In the flat cable high-frequency filter, the first partial conductorpattern and the second partial conductor pattern may be provided on aplurality of dielectric layers forming the dielectric substrate.

With this configuration, the ESR of the inductor is significantlyreduced, and the capacitance of the capacitor is increased.

A flat cable high-frequency diplexer according to a preferred embodimentof the present invention includes a band pass filter configured as theabove-described flat cable high-frequency filter, and a band eliminationfilter constituted by another conductor pattern disposed in thedielectric substrate.

With this configuration, it is possible to provide a thin diplexerexhibiting high transmission characteristics.

An electronic device according to a preferred embodiment of the presentinvention includes one of the above-described flat cable high-frequencyfilters or the flat cable high-frequency diplexer and a plurality ofmount circuit members. The plurality of mount circuit members areconnected to each other by the flat cable high-frequency filter or theflat cable high-frequency diplexer.

With this configuration, even if the flat cable high-frequency filter orthe flat cable high-frequency diplexer is connected between theplurality of mount circuit members, it is possible to reduce the size ofthe entire electronic device and to suppress transmission loss incurredin the plurality of mount circuit members while maintaining thetransmission characteristics of the high-frequency filter or thehigh-frequency diplexer.

In the electronic device, the flat cable high-frequency filter or theflat cable high-frequency diplexer may be disposed with a predeterminedgap from each of the plurality of mount circuit members.

With this configuration, it is possible to significantly reduce orprevent electromagnetic interference between each of the mount circuitmembers and the flat cable high-frequency filter or the flat cablehigh-frequency diplexer.

According to a preferred embodiment of the present invention, it ispossible to implement a space-saving high-frequency filter havingsmall-loss transmission characteristics.

The above and other elements, features, steps, characteristics andadvantages of the present invention will become more apparent from thefollowing detailed description of the preferred embodiments withreference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an external perspective view of a flat cable high-frequencyfilter according to a first preferred embodiment of the presentinvention.

FIG. 2 is an exploded perspective view of the flat cable high-frequencyfilter according to the first preferred embodiment of the presentinvention.

FIG. 3 is an exploded plan view of the flat cable high-frequency filteraccording to the first preferred embodiment of the present invention.

FIG. 4 is an exploded side view of the flat cable high-frequency filteraccording to the first preferred embodiment of the present invention.

FIG. 5A is an equivalent circuit diagram of the flat cablehigh-frequency filter according to the first preferred embodiment of thepresent invention.

FIG. 5B is a graph illustrating filter characteristics of the flat cablehigh-frequency filter according to the first preferred embodiment of thepresent invention.

FIGS. 6A and 6B are respectively a side sectional view and a plansectional view of the arrangement of components forming a mobileelectronic device according to the first preferred embodiment of thepresent invention.

FIGS. 7A and 7B are partial side views illustrating a method for forminga bent portion in a flat cable high-frequency filter.

FIG. 8 is an exploded plan view of a flat cable high-frequency filteraccording to a second preferred embodiment of the present invention.

FIG. 9 is an exploded side view of a flat cable high-frequency filteraccording to a third preferred embodiment of the present invention.

FIG. 10 is an exploded perspective view of a flat cable high-frequencyfilter according to a fourth preferred embodiment of the presentinvention.

FIG. 11 is an exploded perspective view of a flat cable high-frequencyfilter according to a fifth preferred embodiment of the presentinvention.

FIG. 12 is an exploded perspective view of a flat cable high-frequencyfilter according to a sixth preferred embodiment of the presentinvention.

FIG. 13 is an exploded perspective view of a flat cable high-frequencyfilter according to a seventh preferred embodiment of the presentinvention.

FIG. 14 is an equivalent circuit diagram of the flat cablehigh-frequency filter according to the seventh preferred embodiment.

FIG. 15 is an external perspective view of a flat cable high-frequencyfilter according to an eighth preferred embodiment of the presentinvention.

FIG. 16 is an exploded perspective view of the flat cable high-frequencyfilter according to the eighth preferred embodiment.

FIG. 17 is an exploded side view of the flat cable high-frequency filteraccording to the eighth preferred embodiment.

FIGS. 18A and 18B are block diagrams of the configurations of an antennaconnecting portion according to the eighth preferred embodiment.

FIG. 19 is a side view of the configuration of the antenna connectingportion according to the eighth preferred embodiment of the presentinvention.

FIG. 20 is an exploded perspective view of a flat cable high-frequencyfilter according to a ninth preferred embodiment of the presentinvention.

FIG. 21 is an equivalent circuit diagram of the flat cablehigh-frequency filter according to the ninth preferred embodiment of thepresent invention.

FIGS. 22A and 22B are graphs illustrating transmission characteristicsof the flat cable high-frequency filter according to the ninth preferredembodiment of the present invention.

FIG. 23 is an exploded perspective view of a flat cable high-frequencyfilter according to a tenth preferred embodiment of the presentinvention.

FIG. 24 is an exploded perspective view of a flat cable high-frequencyfilter according to an eleventh preferred embodiment of the presentinvention.

FIG. 25 is a block diagram of a communication device module according toa preferred embodiment of the present invention.

FIG. 26 is a side view of the schematic configuration of a communicationdevice module according to a preferred embodiment of the presentinvention.

FIG. 27 is an exploded perspective view of a flat cable high-frequencydiplexer according to a twelfth preferred embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A flat cable high-frequency filter 10 according to a first preferredembodiment of the invention will be described below with reference toFIGS. 1 through 7. FIG. 1 is an external perspective view of the flatcable high-frequency filter 10 of the first preferred embodiment. FIG. 2is an exploded perspective view of the flat cable high-frequency filter10 of the first preferred embodiment. FIG. 3 is an exploded plan view ofthe flat cable high-frequency filter 10 of the first preferredembodiment. FIG. 4 is an exploded side view of the flat cablehigh-frequency filter 10 of the first preferred embodiment.

As shown in FIG. 1, the flat cable high-frequency filter 10 (hereinaftermay also be simply referred to as the “high-frequency filter 10”)includes a dielectric substrate 20, a protecting layer 30 havinginsulating characteristics, and external connection conductors 511 and512. On one principal surface of the dielectric substrate 20, theexternal connection conductors 511 and 512 and the protecting layer 30are disposed. The protecting layer 30 is disposed such that the externalconnection conductors 511 and 512 project from the protecting layer 30and it covers a capacitive coupling conductor pattern 410, which will bediscussed later.

The dielectric substrate 20 is constituted by an elongated flat filmextending in the transmission direction of high-frequency signals andhas a predetermined thickness. The extending direction of the dielectriclayer 20 is a longitudinal direction, and a direction perpendicular tothe longitudinal direction and the thickness direction is a widthwisedirection.

As shown in FIGS. 2, 3, and 4, the dielectric substrate 20 isconstituted by flat, thin dielectric layers 201 and 202 (for example,having a thickness of about 25 μm to about 50 μm) stacked on each otherin the thickness direction. The dielectric substrate 20 (dielectriclayers 201 and 202) is made of a dielectric having a small dielectricloss tangent (tan δ). More preferably, the dielectric substrate 20(dielectric layers 201 and 202) is preferably made of a material havinga dielectric loss tangent equal to or smaller than about 0.005, forexample. More specifically, a liquid crystal polymer may be used for thedielectric substrate 20.

Conductor patterns 401 and 402 are provided on the flat surface of thedielectric layer 201 which faces the dielectric layer 202. The conductorpatterns 401 and 402 are made of a material having a high conductivity,for example, copper (Cu). In the first preferred embodiment, copper foilhaving a thickness of about 10 μm to about 20 μm preferably is used, forexample.

The conductor patterns 401 and 402 preferably have an elongated shape.The longitudinal direction of the conductor patterns 401 and 402 is thesame as that of the dielectric substrate 20. The conductor pattern 401extends from an area near one end of the dielectric layer 201 to about amidpoint of the longitudinal direction thereof, while the conductorpattern 402 extends from an area near the other end of the dielectriclayer 201 to about a midpoint of the longitudinal direction thereof. Theconductor patterns 401 and 402 are not connected to each other. A gap400 is provided between the opposing end portions of the conductorpatterns 401 and 402. The length (length in the longitudinal direction)of the conductor patterns 401 and 402 is determined so as to satisfy adesired inductance of the high-frequency filter 10 as an inductor.

The width of the conductor patterns 401 and 402 is preferably as closeas that of the dielectric substrate 20. In other words, the conductorpatterns 401 and 402 are preferably as wide as possible within a rangein which they can be formed in the dielectric substrate 20. However, asuitable width of the conductor patterns 401 and 402 may be set so as tosatisfy a desired inductance of the high-frequency filter 10 as aninductor. For example, the width of the conductor patterns 401 and 402is preferably about 80% or higher, and more particularly, about 90% ofthat of the dielectric substrate 20. That is, the width of the conductorpatterns 401 and 402 is preferably the same or substantially the same asthat of the dielectric substrate 20. With this configuration, the ESR isreduced to a minimal level while maintaining the environmentalresistance of the conductor patterns 401 and 402.

The capacitive coupling conductor pattern 410 is provided on the flatsurface of the dielectric layer 202 which does not face the dielectriclayer 201. The capacitive coupling conductor pattern 410, as well as theconductor patterns 401 and 402, is made of a material having a highconductivity, for example, copper (Cu). In the first preferredembodiment, copper foil having a thickness of about 10 μm to about 20 μmpreferably is used, for example. The capacitive coupling conductorpattern 410 preferably has an elongated shape. The capacitive couplingconductor pattern 410 opposes, with the intervening dielectric layer202, a region near the end portions of the conductor patterns 401 and402 which oppose each other with the gap 400 therebetween. In this case,the area by which the capacitive coupling conductor pattern 410 opposesthe conductor pattern 402 is determined so as to satisfy a desiredcapacitance of the high-frequency filter 10 as a capacitor.

The capacitive coupling conductor pattern 410 opposes the conductorpattern 401 by an area in which a connecting conductor 60 constituted bya conductive-via passing through the dielectric layer 202 is provided.The capacitive coupling conductor pattern 410 is connected to theconductor pattern 401 via the connecting conductor 60.

The external connection conductor 511 is provided at one end of the flatsurface of the dielectric layer 202 which does not face the dielectriclayer 201. The shape of the external connection conductor 511 is squareor substantially square. The external connection conductor 511 is madeof a material having a high conductivity, for example, copper (Cu). Inthe first preferred embodiment, copper foil having a thickness of about10 μm to about 20 μm preferably is used, for example. The externalconnection conductor 511 is connected to a region near one end portionof the conductor pattern 401 which does not face the conductor pattern402 via the connecting conductor 60 passing through the dielectric layer202.

The external connection conductor 512 is provided at the other end ofthe flat surface of the dielectric layer 202 which does not face thedielectric layer 201. The shape of the external connection conductor 512is square or substantially square. The external connection conductor 512is made of a material having a high conductivity, for example, copper(Cu). The external connection conductor 512 is connected to a regionnear an end portion of the conductor pattern 402 which does not face theconductor pattern 401 via a connecting conductor 60 passing through thedielectric layer 202.

With this configuration of the high-frequency filter 10, ahigh-frequency signal input from the external connection conductor 511is transmitted to the capacitive coupling conductor pattern 410 via theconductor pattern 401. Then, the high-frequency signal is transmitted tothe conductor pattern 402 due to capacitive coupling between thecapacitive coupling conductor pattern 410 and the conductor pattern 402and is output from the external connection conductor 512.

With the configuration of the high-frequency filter 10, the conductorpatterns 401 and 402 define and function as inductors, and the portionby which the capacitive coupling conductor pattern 410 opposes theconductor pattern 402 with the dielectric layer 202 therebetween definesand functions as a capacitor. FIG. 5A is an equivalent circuit diagramof the flat cable high-frequency filter 10 of the first preferredembodiment. With the above-described configuration of the high-frequencyfilter 10, as shown in FIG. 5A, an LC series resonance circuitconstituted by an inductor, a capacitor, and an inductor connected inseries with each other in this order is formed between the externalconnection conductors 511 and 512. In this case, as discussed above, bysuitably determining the configurations of the conductor patterns 401and 402 and the configuration of the capacitive coupling conductorpattern 410, the inductance of each inductor and the capacitance of thecapacitor can be set to be desired values. It is thus possible toimplement a filter in which a desired frequency range is set to be apassband and the frequency ranges outside of the passband are set to beattenuation bands.

With the configuration of the first preferred embodiment, the conductorpatterns 401 and 402 defining and functioning as inductors may be widerthan those forming inductors disposed in a known mounting multilayerbody, thus reducing the ESR of the inductors. It is thus possible toimprove the Q factor of the high-frequency filter 10 and to reducetransmission loss.

It is also possible to increase the area by which the capacitivecoupling conductor pattern 410 opposes the conductor pattern 402. A highcapacitance is obtained without changing the external configuration ofthe flat cable high-frequency filter 10. Accordingly, the range ofcapacitance values necessary as a high-frequency filter is increased,and thus, desired characteristics of a high-frequency filter are alsolikely to be implemented.

With the configuration of the first preferred embodiment, a routingconductor connecting an inductor and a capacitor, which is used in aknown mounting multilayer body, is not required. Thus, unwantedinductance components connected to a capacitor are not generated, thusfurther improving the Q factor of the high-frequency filter 10 andreducing transmission loss.

As discussed above, a material having a very small dielectric losstangent (tan δ) (more specifically, for example, tan δ≦0.005) ispreferably used for the dielectric substrate 20. It is thus possible tofurther improve the Q factor of the high-frequency filter 10 and toreduce transmission loss. In particular, by using a liquid crystalpolymer for the dielectric substrate 20, it is possible to implement ahigh-frequency filter having a high flexibility while implementing theabove-described characteristics.

In the configuration of this preferred embodiment, a ground conductor isnot used, thus preventing the conductor patterns 401 and 402 and thecapacitive coupling conductor pattern 410 from being coupled to aground. Thus, a stray capacitance is not generated, and a desired Qfactor is obtained. It is thus possible to implement a high-frequencyfilter with higher precision and excellent filter characteristics.

FIG. 5B is a graph illustrating filter characteristics of the flat cablehigh-frequency filter 10 of the first preferred embodiment. The filtercharacteristics shown in FIG. 5B are simulation results obtained byusing S parameters (S11 and S21). In this simulation, assuming that thehigh-frequency filter 10 is used for Wi-Fi, the conductor patterns 401and 402 and the capacitive coupling conductor pattern 410 are configuredso that a frequency band of about 2.4 to 5.0 GHz may be set to be thepassband and a frequency band (for example, a 700 MHz band) lower thanthe passband may be contained within the elimination band.

As shown in FIG. 5B, with the configuration of the first preferredembodiment, high-frequency signals of about a 2.4 to 5.0 GHz band canpass through the high-frequency filter 10 with a small transmissionloss, and high-frequency signals of frequency bands outside of thepassband can be attenuated. In particular, it is possible tosignificantly attenuate high-frequency signals in a lower frequency bandthan the passband.

As is seen from the foregoing description, with the configuration of thefirst preferred embodiment, it is possible to implement a thin,space-saving high-frequency filter having high filter characteristicswith small transmission loss.

In the first preferred embodiment, the width WC of the capacitivecoupling conductor pattern 410 and the width WL of the conductorpatterns 401 and 402 are the same. However, it is sufficient that thewidth WC and the width WL be substantially the same. With thisconfiguration, the conductor patterns 401 and 402 defining andfunctioning as inductors are able to be formed wide. This makes itpossible to reduce the ESR of the inductors and to increase the Q factorof the high-frequency filter 10. The ratio of the width WL of theconductor patterns 401 and 402 to the width WC of the capacitivecoupling conductor pattern 410 is preferably a ratio represented by, forexample, 1.0≧WL/WC≧0.8.

The flat cable high-frequency filter 10 configured as described abovemay be used in the following mobile electronic device. FIG. 6A is a sidesectional view of the arrangement of components defining a mobileelectronic device 1 according to the first preferred embodiment. FIG. 6Bis a plan sectional view of the arrangement of the components definingthe mobile electronic device 1.

The electronic device 1 includes a thin device housing 2. Within thedevice housing 2, mount circuit boards 3A and 3B (corresponding to“mount circuit members” in a preferred embodiment of the presentinvention), which are circuit elements, are disposed. A plurality ofintegrated circuit (IC) chips 5 and mount components 6 are mounted onthe surfaces of the mount circuit boards 3A and 3B. The mount circuitboards 3A and 3B are disposed in the device housing 2 such that they areadjacent to each other, as viewing the device housing 2 from above. Themount circuit board 3B is preferably thicker than the mount circuitboard 3A. For example, when the internal circuit in the mount circuitboard 3B is multifunctional and the internal circuit in the mountcircuit board 3A is relatively simple, the thickness of the mountcircuit board 3B is thicker than that of the mount circuit board 3A.

Since the device housing 2 is thin as possible, the distance between themount circuit board 3B and the device housing 2 is very small in thethickness direction of the device housing 2. Accordingly, it isdifficult to dispose a coaxial cable to connect the mount circuit boards3A and 3B.

In contrast, by disposing the flat cable high-frequency filter 10 suchthat the thickness direction of the flat cable high-frequency filter 10coincides with that of the device housing 2, the flat cablehigh-frequency filter 10 is able to be inserted between the mountcircuit boards 3A and 3B and the device housing 2.

Additionally, in a case in which it is necessary to insert ahigh-frequency filter into a transmission path connecting the mountcircuit boards 3A and 3B, the flat cable high-frequency filter 10 of thefirst preferred embodiment may be used. The use of the flat cablehigh-frequency filter 10 is more space-saving than the use of twoseparate components, that is, a flat cable, which is a transmissionline, and a high-frequency filter. It is also possible to make anelectronic device thinner by using the flat cable high-frequency filter10 than that using a high-frequency filter constituted by mountcomponents of a multilayer body.

The flat cable high-frequency filter 10 of the first preferredembodiment has flexibility so that it can be curved or bent.Accordingly, even if the thicknesses of the mount circuit boards 3A and3B are different, the flat cable high-frequency filter 10 can bedisposed efficiently within the device housing 2, thus saving space inthe arrangement of the flat cable high-frequency filter 10.

In this case, the curving or bending position of the flat cablehigh-frequency filter 10 is a position other than the region in whichthe capacitor is located, that is, the region in which the capacitivecoupling conductor pattern 410 is located. This prevents a fluctuationin the capacitance caused by the curving or the bending of the flatcable high-frequency filter 10, thus implementing desired filtercharacteristics.

When curving or bending the flat cable high-frequency filter 10, bysuitably setting the thickness of the dielectric layers 201 and 202 ofthe dielectric substrate 20 having flexibility and the thickness of thecapacitive coupling conductor pattern 410 having a certain level ofstiffness, the curved or bent shape is able to be maintained. Morespecifically, the thickness of the dielectric layers 201 and 202 may beset to be about 25 μm to about 50 μm, for example, and the thickness ofthe conductor patterns 401 and 402 and the capacitive coupling conductorpattern 410 may be set to be about half the thickness of the dielectriclayers 201 and 202, for example.

With this configuration, as shown in FIGS. 6A and 6B, the flat cablehigh-frequency filter 10 can be disposed separately from (not in contactwith) the mount circuit boards 3A and 3B. It is thus possible to reduceelectromagnetic interference between the flat cable high-frequencyfilter 10 and the mount circuit boards 3A and 3B, thus improvingtransmission characteristics between the mount circuit boards 3A and 3Band high-frequency filter characteristics. In particular, if the flatcable high-frequency filter 10 is separated from the mount circuitboards 3A and 3B by about 100 μm or greater, the effect of reducingelectromagnetic interference is sufficiently exhibited.

A bent shape of the flat cable high-frequency filter 10 may be formed byusing a method shown in FIGS. 7A and 7B. FIGS. 7A and 7B are partialside views illustrating a method for forming a bent portion in the flatcable high-frequency filter 10. FIG. 7A illustrates the flat cablehigh-frequency filter 10 and tools for forming a bent portion in theflat cable high-frequency filter 10. FIG. 7B illustrates the flat cablehigh-frequency filter 10 after a bent portion is formed.

As shown in FIG. 7A, the flat cable high-frequency filter 10 is clampedbetween a first tool 901 including a step 911 in the thickness directionand a second tool 902 including a step 912 in the thickness direction.In this case, the first and second tools 901 and 902 clamp the flatcable high-frequency filter 10 therebetween so that the steps 911 and912 clamp the flat cable high-frequency filter 10 therebetween whileabutting both surfaces of the flat cable high-frequency filter 10. Ifnecessary, heat is applied. Then, the flat cable high-frequency filter10 can be bent at a certain position in the longitudinal direction.

The edge portions of the steps 911 and 912 are beveled and define around beveled shape in cross section. With the configuration of thesteps 911 and 912, a bent portion Be10 can be formed without damagingthe flat cable high-frequency filter 10.

A flat cable high-frequency filter 10A according to a second preferredembodiment will be described below with reference to the exploded planview of FIG. 8. The flat cable high-frequency filter 10A is differentfrom the flat cable high-frequency filter 10 of the first preferredembodiment only in the configuration of a capacitive coupling conductorpattern 410W. Accordingly, portions different from the first preferredembodiment will be discussed specifically.

The width WCA of the capacitive coupling conductor pattern 410W of theflat cable high-frequency filter 10A is greater than the width WL of theconductor patterns 401 and 402. With this configuration, as well as theconfiguration of the first preferred embodiment, an LC series resonancecircuit can also be provided, and advantages similar to those of thefirst preferred embodiment are obtained. The ratio of the width WL ofthe conductor patterns 401 and 402 to the width WCA of the capacitivecoupling conductor pattern 410W is preferably a ratio represented by,for example, 1.0≧WL/WCA≧0.8.

With the configuration of the second preferred embodiment, when stackingthe dielectric layers 201 and 202, even if the widthwise positions ofthe dielectric layers 201 and 202 are displaced from each other, theareas by which the capacitive coupling conductor pattern 410W opposesthe conductor patterns 401 and 402 do not change if the displacementamount is within a difference between the widths WCA and WL.Accordingly, the flat cable high-frequency filter 10A having a desiredcapacitance is more easily manufactured. Additionally, a variation inthe characteristics among flat cable high-frequency filters as productsis significantly reduced or prevented.

A flat cable high-frequency filter 10B according to a third preferredembodiment will be described below with reference to the exploded sideview of FIG. 9. The flat cable high-frequency filter 10B is differentfrom the flat cable high-frequency filter 10 of the first preferredembodiment in the configuration of a capacitive coupling conductorpattern 410B and the relationship between the capacitive couplingconductor pattern 410B and the conductor pattern 401. Accordingly,portions different from the first preferred embodiment will be discussedspecifically.

The capacitive coupling conductor pattern 410B opposes the conductorpattern 401 by a predetermined area. The capacitive coupling conductorpattern 410B is not connected to the conductor pattern 401 by aconnecting conductor 60. In other words, the capacitive couplingconductor pattern 410B and the conductor pattern 401 merely oppose eachother with the dielectric layer 202 therebetween.

With this configuration, it is possible to provide an LC seriesresonance circuit constituted by an inductor, a capacitor, a capacitor,and an inductor connected in series with each other in this order. Bysuitably setting the areas by which the capacitive coupling conductorpattern 410B opposes the conductor patterns 401 and 402, a desiredcapacitance of each capacitor can be obtained. Thus, advantages similarto those of the first preferred embodiment are implemented.

With the configuration of the second preferred embodiment, even if theposition at which the dielectric layers 201 and 202 are stacked islongitudinally displaced from each other, the area by which thecapacitive coupling conductor pattern 410B opposes the conductor pattern401 and that by which capacitive coupling conductor pattern 410B opposesthe conductor pattern 402 are offset by each other in the followingmanner. If the area by which the capacitive coupling conductor pattern410B opposes the conductor pattern 401 increases, the area by which thecapacitive coupling conductor pattern 410B opposes the conductor pattern402 decreases, and if the area by which the capacitive couplingconductor pattern 410B opposes the conductor pattern 401 decreases, thearea by which the capacitive coupling conductor pattern 410B opposes theconductor pattern 402 increases. Accordingly, it is possible tosignificantly reduce or prevent a fluctuation in the capacitance causedby the positional displacement when stacking the dielectric layers 201and 202. Thus, the flat cable high-frequency filter 10B having a desiredcapacitance is more reliably manufactured. Additionally, a variation inthe characteristics among flat cable high-frequency filters as productsis significantly reduced or prevented.

A flat cable high-frequency filter 10C according to a fourth preferredembodiment will be described below with reference to the explodedperspective view of FIG. 10. The flat cable high-frequency filter 10C isdifferent from the flat cable high-frequency filter 10 of the firstpreferred embodiment only in the configuration of a conductor pattern401C. Accordingly, portions different from the first preferredembodiment will be discussed specifically.

The conductor pattern 401C is provided on the surface of the dielectriclayer 202 which does not face the dielectric layer 201. One longitudinalend of the conductor pattern 401C is connected to the externalconnection conductor 511. A predetermined region near the other end ofthe external connection conductor 511 opposes the conductor pattern 402by a predetermined area.

With this configuration, advantages similar to those of the firstpreferred embodiment is obtained. Additionally, in the configuration ofthe fourth preferred embodiment, since the conductor pattern 401C isconnected to the external connection conductor 511 in the same plane,the number of connecting conductors is reduced. This makes it possibleto simplify the structure of the flat cable high-frequency filter 10Cand also to improve the reliability.

A flat cable high-frequency filter 10D according to a fifth preferredembodiment will be described below with reference to the explodedperspective view of FIG. 11.

The flat cable high-frequency filter 10D is preferably made of the samematerial as the flat cable high-frequency filter 10 of the firstpreferred embodiment, but the configurations of a dielectric substrate20D and conductor patterns 401D and 402D are different from those of thefirst preferred embodiment. Accordingly, portions different from thefirst preferred embodiment will be discussed specifically.

The dielectric substrate 20D preferably is constituted by a singlelayer. The conductor patterns 401D and 402D are provided on one flatsurface of the dielectric substrate 20D. The conductor patterns 401D and402D are arranged side by side in the longitudinal direction of thedielectric substrate 20D.

An external connection conductor 511 is located at one longitudinal endof the dielectric substrate 20D, while an external connection conductor512 is located at the other longitudinal end of the dielectric substrate20D. The conductor pattern 401D is connected to the external connectionconductor 511, while the conductor pattern 402D is connected to theexternal connection conductor 512.

An interdigital capacitive coupling conductor pattern 411D is locatednear an end portion of the conductor pattern 401D adjacent to theconductor pattern 402D (end portion which does not face the externalconnection conductor 511). An interdigital capacitive coupling conductorpattern 412D is located near an end portion of the conductor pattern402D adjacent to the conductor pattern 401D (end portion which does notface the external connection conductor 512).

The capacitive coupling conductor patterns 411D and 412D are disposedsuch that conductor fingers extending in the longitudinal directionoppose each other in the longitudinal direction by a predeterminedlength with a predetermined space in the widthwise direction between theconductor fingers of the capacitive coupling conductor patterns 411D and412D. With this configuration, a capacitor is provided on the flatsurface of the single-layer dielectric substrate 20D.

With this configuration, advantages similar to those of the firstpreferred embodiment are obtained. Additionally, in the configuration ofthe fifth preferred embodiment, since the single-layer dielectricsubstrate 20D is used, the structure of the flat cable high-frequencyfilter 10D is further simplified and the thickness thereof is furtherreduced. As a result, the reliability is improved.

A flat cable high-frequency filter 10E according to a sixth preferredembodiment will be described below with reference to the explodedperspective view of FIG. 12.

The flat cable high-frequency filter 10E of the sixth preferredembodiment is configured such that shield conductors 711, 712, 721, and722 are added to the flat cable high-frequency filter 10C of the fourthpreferred embodiment. Accordingly, portions different from the fourthpreferred embodiment will be discussed specifically.

A dielectric substrate 20E is constituted by dielectric layers 201, 202,211, and 212 stacked on each other. The dielectric layers 211 and 212are disposed such that they sandwich the dielectric layers 201 and 202therebetween. The dielectric layer 211 abuts against the dielectriclayer 201, while the dielectric layer 212 abuts against the dielectriclayer 202.

A conductor pattern 402E and a capacitive coupling conductor pattern412E are provided on the flat surface of the dielectric layer 201 whichfaces the dielectric layer 202. A conductor pattern 401E and acapacitive coupling conductor pattern 411E are provided on the flatsurface of the dielectric layer 202 which faces the dielectric layer212.

The capacitive coupling conductor patterns 411E and 412E oppose eachother with the dielectric layer 202 therebetween.

The shield conductors 711 and 712 and external connection conductors 511and 512 are provided on the flat surface of the dielectric layer 212which does not face the dielectric layer 202. The external connectionconductor 511 is connected to the conductor pattern 401E by a connectingconductor 60. The external connection conductor 512 is connected to theconductor pattern 402E by a connecting conductor 60.

The shield conductors 721 and 722 are provided on the flat surface ofthe dielectric layer 211 which faces the dielectric layer 201.

The shield conductors 711 and 721 are disposed such that they aresuperposed on the conductor pattern 401E and are superposed neither onthe capacitive coupling conductor pattern 411E nor 412E, as viewed inthe thickness direction. The shield conductors 712 and 722 are disposedsuch that they are superposed on the conductor pattern 402E and aresuperposed neither on the capacitive coupling conductor pattern 411E nor412E, as viewed in the thickness direction.

With this configuration, the conductor patterns 401E and 402E areprevented from electromagnetically interfering with an external circuit.It is also possible to significantly reduce or prevent a fluctuation inthe capacitance of the capacitors defined by the capacitive couplingconductor patterns 411E and 412E caused by the shield conductors 711,712, 721, and 722. Therefore, a flat cable high-frequency filterexhibiting high transmission characteristics and filter characteristicsis implemented.

The above-described shield conductor may be located at at least one ofthe above-described four positions. In this case, at least advantagesunique to the sixth preferred embodiment are obtained.

The shield conductors 711, 712, 721, and 722 may be solid conductors, asshown in FIG. 12, or may be mesh-shaped conductors.

A flat cable high-frequency filter 10F according to a seventh preferredembodiment will be described below with reference to FIGS. 13 and 14.FIG. 13 is an exploded perspective view of the flat cable high-frequencyfilter 10F of the seventh preferred embodiment.

The flat cable high-frequency filter 10F is different from the flatcable high-frequency filter 10 of the first preferred embodiment only inthe configuration of conductor patterns. Accordingly, portions differentfrom the first preferred embodiment will be discussed specifically.

Capacitive coupling conductor patterns 410F and 411F are provided on theflat surface of a dielectric layer 201 which faces the dielectric layer202. Conductor patterns 401F, 402F, and 403F are provided on the flatsurface of the dielectric layer 202 which does not face the dielectriclayer 201. The conductor patterns 401F, 402F, and 403F are arranged sideby side in the longitudinal direction of the dielectric layer 202.

One end of the conductor pattern 401F is connected to an externalconnection conductor 511, and the other end of the conductor pattern401F is connected to the capacitive coupling conductor pattern 410F by aconnecting conductor 60.

One end of the conductor pattern 403F is connected to an externalconnection conductor 512, and the other end of the conductor pattern403F is connected to the capacitive coupling conductor pattern 411F by aconnecting conductor 60.

A predetermined region near one end of the conductor pattern 402Fopposes the capacitive coupling conductor pattern 410F by apredetermined area. A predetermined region near the other end of theconductor pattern 402F opposes the capacitive coupling conductor pattern411F by a predetermined area.

With this configuration, the conductor pattern 402F defines andfunctions as an inductor. Portions at which the capacitive couplingconductor patterns 410F and 411F oppose the conductor pattern 402F withthe dielectric layer 202 therebetween define and function as capacitors.FIG. 14 is an equivalent circuit diagram of the flat cablehigh-frequency filter 10F according to the seventh preferred embodiment.With the above-described configuration, as shown in FIG. 14, an LCseries resonance circuit constituted by a capacitor, an inductor, and acapacitor connected in series with each other in this order is providedbetween the external connection conductors 511 and 512. In this case, asdiscussed above, by suitably determining the configuration of theconductor pattern 402F and the configurations of the capacitive couplingconductor patterns 410F and 411F, the inductance of the inductor and thecapacitance of each capacitor is set to be desired values. It is thuspossible to implement a filter in which a desired frequency range is setto be a passband and the frequency ranges outside of the passband areset to be attenuation bands.

The flat cable high-frequency filter 10F has flexibility, so that it isable to be disposed by being curved or bent. In this case, the curvingor bending position of the flat cable high-frequency filter 10F is aposition other than the region in which the capacitors are located, thatis, the region in which the capacitive coupling conductor patterns 410Fand 411F are located. This prevents a fluctuation in the capacitancecaused by the curving or the bending of the flat cable high-frequencyfilter 10F, thus implementing desired filter characteristics.

A flat cable high-frequency filter 10G according to an eighth preferredembodiment will be described below with reference to FIGS. 15 through19. FIG. 15 is an external perspective view of the flat cablehigh-frequency filter 10G of the eighth preferred embodiment. FIG. 16 isan exploded perspective view of the flat cable high-frequency filter 10Gof the eighth preferred embodiment. FIG. 17 is an exploded side view ofthe flat cable high-frequency filter 10G of the eighth preferredembodiment.

The flat cable high-frequency filter 10G is different from the flatcable high-frequency filter 10C of the fourth preferred embodiment inthe position of an external connection conductor 512G. Accordingly,portions different from the fourth preferred embodiment will bediscussed specifically.

A dielectric substrate 20 is constituted by dielectric layers 201, 202,and 211 stacked on each other. The dielectric layers 202 and 211 aredisposed with the dielectric layer 201 therebetween. The dielectriclayer 211 abuts against the dielectric layer 201.

The external connection conductor 512G is provided on the flat surfaceof the dielectric layer 211 which does not face the dielectric layer201. The external connection conductor 512G is connected to a conductorpattern 402 by a connecting conductor 60.

Protecting layers 301 and 302 are disposed with the dielectric substrate20 therebetween. The protecting layer 301 is disposed such that theexternal connection conductor 512G projects from the protecting layer301. The protecting layer 302 is disposed such that an externalconnection conductor 511 projects from the protecting layer 302 and thatit covers a conductor pattern 401C.

A connector 611 is provided on one principal surface of the flat cablehigh-frequency filter 10G and is connected to the external connectionconductor 511. A connector 612 is provided on the other principalsurface of the flat cable high-frequency filter 10G and is connected tothe external connection conductor 512G.

The region by which the conductor pattern 401C opposes the conductorpattern 402, that is, a region in which a capacitor is located, isdisposed near the connector 612.

The flat cable high-frequency filter 10G configured as described abovemay be used in the following antenna connecting portion. FIGS. 18A and18B are block diagrams of the configurations of an antenna connectingportion according to the eighth preferred embodiment. FIG. 19 is a sideview of the configuration of the antenna connecting portion according tothe eighth preferred embodiment.

As shown in FIG. 18A, the flat cable high-frequency filter 10G isconnected between an antenna 52 and a feeder circuit 51. The nodebetween the antenna 52 and the flat cable high-frequency filter 10G isconnected to a ground.

The antenna connecting portion may be formed in another configuration,such as that shown in FIG. 18B. In FIG. 18B, the flat cablehigh-frequency filter 10G is connected between the antenna 52 and aground. The feeder circuit 51 is connected to the node between theantenna 52 and the flat cable high-frequency filter 10G.

As shown in FIG. 19, the feeder circuit 51 includes a mount board 3, ICchips 5, and mount components 6. A plurality of IC chips 5 and aplurality of mount components 6 are mounted on the surface of the mountboard 3. The antenna 52 is disposed at a position separated from themount board 3.

The connector 611 of the flat cable high-frequency filter 10G isconnected to the antenna 52, while the connector 612 is connected to thefeeder circuit 51. That is, the region in which the capacitor of theflat cable high-frequency filter 10G is located is spaced from theantenna 52.

If the antenna 52 is disposed near the capacitor forming region, the Qfactor is decreased. With this configuration, the capacitor formingregion is spaced from the antenna 52 by a certain distance, thussuppressing a decrease in the antenna characteristics. The portion ofthe flat cable high-frequency filter 10G which is closer to the antenna52 than the capacitor forming region is a linear conductor. Accordingly,this portion is able to be used as a portion of the antenna.

As discussed above, the bending or curving position of the flat cablehigh-frequency filter 10G is a position other than the capacitor formingregion. This prevents a fluctuation in the capacitance caused by thecurving or the bending of the flat cable high-frequency filter 10G, thusimplementing desired filter characteristics. If this bending or curvingposition is set as close as to the capacitor forming region, the portionof the flat cable high-frequency filter 10G that is able to also be usedas the antenna is increased. If this bending or curving position ischanged, the impedance of the antenna is adjusted.

The connector 611 is provided on one principal surface of the flat cablehigh-frequency filter 10G, while the connector 612 is provided on theopposite principal surface. Accordingly, it is not necessary to bend andturn over the flat cable high-frequency filter 10G only for the purposeof connecting the connectors 611 and 612 to the antenna 52 and thefeeder circuit 51, respectively. Thus, even with a very small spacebetween the antenna 52 and the mount board 3, the flat cablehigh-frequency filter 10G is able to be inserted therebetween.

Even in a case in which the antenna 52 is disposed on an IC chip 5 or amount component 6, the flat cable high-frequency filter 10G may be bentor curved so as to be inserted between the antenna 52 and the mountboard 3.

A flat cable high-frequency filter 10H according to a ninth preferredembodiment will be described below with reference to FIGS. 20 through22B. FIG. 20 is an exploded perspective view of the flat cablehigh-frequency filter 10H of the ninth preferred embodiment. In FIG. 20,protecting layers and connectors are not shown.

As in the flat cable high-frequency filter 10 of the first preferredembodiment, in the flat cable high-frequency filter 10H of the ninthpreferred embodiment, a connecting portion to be connected to anexternal circuit is provided on one principal surface of a dielectricsubstrate 20H. The components of the flat cable high-frequency filter10H are substantially the same as those of the above-described preferredembodiments. Accordingly, portions unique to the ninth preferredembodiment will be described specifically.

The flat cable high-frequency filter 10H includes a flat dielectricsubstrate 20H. The dielectric substrate 20H are constituted bydielectric layers 201H, 202H, 203H, and 204H sequentially stacked oneach other.

Conductor patterns 401H1 and 403H1 are provided on a principal surfaceof the dielectric layer 201H which does not face the dielectric layer202H (on one principal surface of the dielectric substrate 20H). Theconductor pattern 401H1 includes a first partial conductor pattern401H11 and a second partial conductor pattern 401H12.

The first partial conductor pattern 401H11 and the conductor pattern403H1 are disposed along the longitudinal direction of the dielectriclayer 201H with a space therebetween. The first partial conductorpattern 401H11 and the conductor pattern 403H1 have the same orsubstantially the same width, which is wider than the second partialconductor pattern 401H12. In terms of the functions of the first partialconductor pattern 401H11 and the conductor pattern 403H1, they each havea width sufficient to define a capacitor, which will be discussed below.

The second partial conductor pattern 401H12 is disposed adjacent to thefirst partial conductor pattern 401H11 along the widthwise direction ofthe dielectric layer 201H. The second partial conductor pattern 401H12is a loop shaped conductor pattern. The loop shaped conductor pattern isa pattern formed in a loop shape, a portion of which is removed.

An end of one side portion of the first partial conductor pattern 401H11(one end of the dielectric layer 201H) and one end (outer peripheralend) of the second partial conductor pattern 401H12 are connected toeach other near one end of the dielectric layer 201H. The first andsecond partial conductor patterns 401H11 and 401H12 are connected to anextended conductor pattern 441 located at one end of the dielectriclayer 201H.

An end of one side portion of the conductor pattern 403H1 (the other endof the dielectric layer 201H) is connected to an extended conductorpattern 442 located at the other end of the dielectric layer 201H.

On the principal surface of the dielectric layer 202H which faces thedielectric layer 201H, a conductor pattern 401H2 and a capacitivecoupling conductor pattern 410H1 are provided. The conductor pattern401H2 includes a first partial conductor pattern 401H21 and a secondpartial conductor pattern 401H22.

The first partial conductor pattern 401H21 preferably is rectangular orsubstantially rectangular and opposes a portion of the first partialconductor pattern 401H11 with the dielectric layer 201H therebetween.The first partial conductor pattern 401H21 is connected to the firstpartial conductor pattern 401H11 by a connecting conductor 60 passingthrough the dielectric layer 201H in the thickness direction.

The second partial conductor pattern 401H22 is disposed adjacent to thefirst partial conductor pattern 401H21 along the widthwise direction ofthe dielectric layer 202H. The second partial conductor pattern 401H22is a loop shaped conductor pattern. The second partial conductor pattern401H22 is superposed on the second partial conductor pattern 401H12, asviewed in the direction perpendicular to the principal surface. One end(outer peripheral end) of the second partial conductor pattern 401H22 isconnected to the first partial conductor pattern 401H21. The other end(inner peripheral end) of the second partial conductor pattern 401H22 isconnected to the other end (inner peripheral end) of the second partialconductor pattern 401H12 by a connecting conductor 60 passing throughthe dielectric layer 201H in the thickness direction.

The capacitive coupling conductor pattern 410H1 preferably isrectangular or substantially rectangular and opposes both of the firstpartial conductor pattern 401H11 and the conductor pattern 403H1 withthe dielectric layer 201H therebetween. The portion by which thecapacitive coupling conductor pattern 410H1 opposes the first partialconductor pattern 401H11 that defines or functions as a capacitor C21H.The portion by which capacitive coupling conductor pattern 410H1 opposesthe conductor pattern 403H1 defines and functions as a capacitor C10H.

On the principal surface of the dielectric layer 203H which faces thedielectric layer 202H, a capacitive coupling conductor pattern 410H2 anda conductor pattern 402H1 are provided. The conductor pattern 402H1includes a first partial conductor pattern 402H11 and a second partialconductor pattern 402H12.

The capacitive coupling conductor pattern 410H2 and the first partialconductor pattern 402H11 are disposed along the longitudinal directionof the dielectric layer 203H with a space therebetween. The capacitivecoupling conductor pattern 410H2 and the first partial conductor pattern402H11 have the same or substantially the same width. The capacitivecoupling conductor pattern 410H2 is connected to the first portionconductor patter 401H21 by a connecting conductor 60 passing through thedielectric layer 202H in the thickness direction.

The first partial conductor pattern 402H11 preferably is rectangular orsubstantially rectangular and opposes part of the capacitive couplingconductor pattern 410H1 with the dielectric layer 202H therebetween. Thefirst partial conductor pattern 402H11 is connected to the capacitivecoupling conductor pattern 410H1 by a connecting conductor 60 passingthrough the dielectric layer 202H in the thickness direction.

The second partial conductor pattern 402H12 is disposed adjacent to thecapacitive coupling conductor pattern 410H2 along the widthwisedirection of the dielectric layer 203H. The second partial conductorpattern 402H12 is a loop shaped conductor pattern. One end (outerperipheral end) of the second partial conductor pattern 402H12 isconnected to the first partial conductor pattern 402H11. The other end(inner peripheral end) of the second partial conductor pattern 402H12 issuperposed on the other ends (inner peripheral ends) of the secondpartial conductor patterns 401H22 and 401H12, as viewed in the directionperpendicular to the principal surface. The other end (inner peripheralend) of the second partial conductor pattern 402H12 is connected to theother end (inner peripheral end) of the second partial conductor pattern401H22 by a connecting conductor 60 passing through the dielectric layer202H.

The capacitive coupling conductor pattern 410H2 preferably isrectangular or substantially rectangular and opposes both of the firstpartial conductor pattern 401H21 and the capacitive coupling conductorpattern 410H1 with the dielectric layer 202H therebetween. Thecapacitive coupling conductor pattern 410H2 is connected to the firstpartial conductor pattern 401H21 by a connecting conductor 60 passingthrough the dielectric layer 202H in the thickness direction. Theportion by which the capacitive coupling conductor patterns 410H1 and410H2 oppose each other defines and functions as a capacitor C22H.

On the principal surface of the dielectric layer 204H which faces thedielectric layer 203H, a conductor pattern 402H2 is provided. Theconductor pattern 402H2 includes a first partial conductor pattern402H21 and a second partial conductor pattern 402H22.

The first partial conductor pattern 402H21 preferably is rectangular orsubstantially rectangular and opposes a portion of the capacitivecoupling conductor pattern 410H2 and the first partial conductor pattern402H11 with the dielectric layer 203H therebetween. The first partialconductor pattern 402H21 is connected to the first partial conductorpattern 402H11 by a connecting conductor 60 passing through thedielectric layer 203H in the thickness direction. The portion by whichthe first partial conductor pattern 402H21 opposes the capacitivecoupling conductor pattern 410H2 defines and functions as a capacitorC23H.

The second partial conductor pattern 402H22 is a loop shaped conductorpattern. The second partial conductor pattern 402H22 is superposed onthe second partial conductor pattern 402H12, as viewed in the directionperpendicular to the principal surface. One end (outer peripheral end)of the second partial conductor pattern 402H22 is connected to the firstpartial conductor pattern 402H21. The other end (inner peripheral end)of the second partial conductor pattern 402H22 is connected to the otherend (inner peripheral end) of the second partial conductor pattern402H12 by a connecting conductor 60 passing through the dielectric layer203H in the thickness direction.

The second partial conductor patterns 401H12, 401H22, 402H12, and 402H22are disposed as described above, and the inner peripheral ends thereofare connected to each other by the connecting conductor 60, thusdefining a spiral inductor L10H having an axis in the thicknessdirection of the dielectric substrate 20H.

With this configuration, the flat cable high-frequency filter 10H of theninth preferred embodiment defines a circuit shown in the equivalentcircuit diagram of FIG. 21.

A series circuit of the inductor L10H and a capacitor C10H is connectedbetween the extended conductor patterns 441 and 442. The capacitorsC21H, C22H, and C23H are connected in parallel with the inductor L10H.That is, it is possible to provide a filter circuit including both of anLC series resonance circuit and an LC parallel resonance circuit.

With this circuit configuration, it is possible to obtain transmissioncharacteristics shown in FIGS. 22A and 22B. FIGS. 22A and 22B are graphsillustrating transmission characteristics of the flat cablehigh-frequency filter 10H according to the ninth preferred embodiment.FIG. 22A illustrates band pass characteristics, while FIG. 22Billustrates reflection characteristics. In the ninth preferredembodiment, the device values of the inductor L10H and the capacitorsC10H, C21H, C22H, and C23H are determined so as to obtaincharacteristics in which a high-frequency signal at frequency f0 passesthrough the flat cable high-frequency filter 10H and a high-frequencysignal at frequency f1 is attenuated. That is, the configurations of thedielectric substrate 20H and the conductor patterns are determined so asto implement these device values.

With the configuration of the ninth preferred embodiment, ahigh-frequency signal at frequency f0, which is a passband frequency, isable to be transmitted at a small loss, as shown in FIG. 22A, and ahigh-frequency signal at frequency f1, which is an attenuationfrequency, is attenuated significantly, as shown in FIG. 22B.

In this case, as shown in FIGS. 22A and 22B, even if the frequency f0,which is a passband frequency, and the f1, which is the attenuationfrequency, are close to each other, it is possible to transmit ahigh-frequency signal at frequency f0 at a small loss and tosignificantly attenuate a high-frequency signal at frequency f1. Morespecifically, the frequency f0 is a global positioning system (GPS)signal frequency, which is about 1.575 GHz, while the frequency f1 is acommunication band signal, which is 1.7 GHz band signal. In this manner,even if the frequency difference is about 200 MHz, it is possible totransmit a high-frequency signal at frequency f0 (1.575 GHz) at a smallloss and to significantly attenuate a high-frequency signal at frequencyf1 (1.7 GHz band).

As described above, with the configuration of the ninth preferredembodiment, it is possible to provide a filter which exhibits a sharpattenuation at a high frequency side of a passband.

In the configuration of the ninth preferred embodiment, portions ofconductor patterns defining the inductor L10H are disposed on aplurality of layers. This makes it possible to reduce the ESR of theinductor L10H and also to implement sharp, small loss transmission andattenuation characteristics.

A flat cable high-frequency filter 10I according to a tenth preferredembodiment will be described below with reference to the explodedperspective view of FIG. 23. In FIG. 23, as well as in FIG. 20,protecting layers and connectors are not shown.

The flat cable high-frequency filter 10I is different from the flatcable high-frequency filter 10H of the ninth preferred embodiment in theconfigurations of some conductor patterns. The configurations of theother components are basically the same as those of the ninth preferredembodiment.

The flat cable high-frequency filter 10I includes a dielectric substrate20I constituted by dielectric layers 201I, 202I, 203I, and 204I stackedon each other. The configurations of the conductor patterns on thedielectric layers 201I, 202I, and 203I are the same as those of thedielectric layers 201H, 202H, and 203H of the ninth preferredembodiment.

On the principal surface of the dielectric layer 204I which does notface the dielectric layer 203I, a conductor pattern 402I2 and anextended conductor 443 are provided. The conductor pattern 402I2 isplane-symmetrical to the conductor pattern 402H2 of the ninth preferredembodiment with respect to the principal surface of the dielectric layerused as a reference plane. The extended conductor 443 is configured suchthat it is superposed on the extended conductor 441, as viewed in thedirection perpendicular to the principal surface of the dielectricsubstrate 20I. The extended conductor 443 is connected to the extendedconductor 441 by a connecting conductor 60 passing through thedielectric layers 201I, 202I, 203I, and 204I, that is, the dielectricsubstrate 20I. The extended conductor 443 is connected to an externalconnection conductor and a connector, and the extended conductor 441 isnot exposed to the outside.

With this configuration, advantages similar to those of the ninthpreferred embodiment are obtained. Additionally, as in the eighthpreferred embodiment, one external connection portion of the flat cablehigh-frequency filter 10I is disposed on one principal surface of thedielectric substrate 20I, and the other external connection portion isdisposed on the other principal surface of the dielectric substrate 20I.With this configuration, even if external circuit boards to be connectedto the flat cable high-frequency filter 10I are disposed with the flatcable high-frequency filter 10I therebetween in the thickness direction,the external circuit boards are easily connected via the flat cablehigh-frequency filter 10I.

A flat cable high-frequency filter 10J according to an eleventhpreferred embodiment will be described below with reference to theexploded perspective view of FIG. 24. In FIG. 24, as well as in FIGS. 20and 23, protecting layers and connectors are not shown.

The flat cable high-frequency filter 10J is a filter from which twodielectric layers are removed from the flat cable high-frequency filter10I of the tenth preferred embodiment. The configurations of the otherelements are basically the same as those of the tenth preferredembodiment.

The flat cable high-frequency filter 10J includes a dielectric substrate20J constituted by dielectric layers 201J and 204J stacked on eachother. The configurations of the conductor patterns disposed on thedielectric layers 201J and 204J are the same as those on the dielectriclayers 201I and 204I of the tenth preferred embodiment. A first partialconductor pattern 402J21 also defines and functions as a capacitivecoupling conductor pattern.

With this configuration, advantages similar to those of the tenthpreferred embodiment are obtained. In the flat cable high-frequencyfilter 10J of the eleventh preferred embodiment, however, only onecapacitor is connected in parallel with the inductor. Thus, if desiredtransmission characteristics are obtained by the flat cablehigh-frequency filter 10J, the configuration of the eleventh preferredembodiment may be used. With the configuration of the eleventh preferredembodiment, the number of dielectric layers is reduced, thus making itpossible to make the flat cable high-frequency filter 10J even thinner.

The flat cable high-frequency filters of the above-described preferredembodiments implementing band pass filters may be used in the followingcommunication device module. FIG. 25 is a block diagram of acommunication device module 900 according to a preferred embodiment ofthe present invention. FIG. 26 is a side view of the schematicconfiguration of the communication device module 900 according to apreferred embodiment of the present invention. In the communicationdevice module 900 shown in FIGS. 25 and 26, the flat cablehigh-frequency filter 10I of the tenth preferred embodiment is used.

As shown in FIG. 25, the communication device module 900 preferablyincludes an antenna 930, a WiFi transmitter-receiver 931, a cellulartransmitter-receiver 932, a GPS receiver 933, a band elimination filter(BEF) 921, and a band pass filter (BPF) 922.

The antenna 930 is connected to the WiFi transmitter-receiver 931 andthe cellular transmitter-receiver 932 via the BEF 921, and is connectedto the GPS receiver 933 via the BPF 922.

The WiFi transmitter-receiver 931 transmits and receives WiFicommunication signals using a frequency band, for example, a 2.4 GHzband. The cellular transmitter-receiver 932 transmits and receivescellular communication signals using frequency bands, for example, 900MHz, 1.7 GHz, and 2.0 GHz. The GPS receiver 933 receives GPS signalsusing a frequency band near 1.5 GHz.

The BEF 921 attenuates the frequency band of GPS signals, and allows thefrequency bands of WiFi communication signals and cellular communicationsignals to pass through the BEF 921. The BPF 922 allows the frequencyband of GPS signals to pass through the BPF 922, and attenuates thefrequency bands other than the frequency band of GPS signals.

The flat cable high-frequency filter 10I of the tenth preferredembodiment is preferably used as the BPF 922. By the use of the flatcable high-frequency filter 10I, it is possible to implement a BEFhaving sharp attenuation characteristics with a narrow attenuation band.Accordingly, if an attenuation pole is set in a frequency band of a GPSsignal, it is possible to attenuate a GPS signal and to transmit anothercommunication signal in a frequency band (for example, a cellularcommunication signal in a 1.7 GHz band) near the frequency band of theGPS signal without attenuating the communication signal.

As shown in FIG. 26, the communication device module 900 having theabove-described circuit configuration includes a front end substrate990, an antenna substrate 991, and the flat cable high-frequency filter10I. On the mount surface of the front end substrate 990, circuitcomponents implementing, for example, the above-described WiFitransmitter-receiver 931, the cellular transmitter-receiver 932, and theGPS receiver 933, are mounted. On the antenna substrate 991, the antenna930 is provided. The antenna substrate 991 is disposed such that itfaces the mount surface of the front end substrate 990 separately fromthe front end substrate 990.

As shown in FIG. 26, the connector 611 attached to the flat cablehigh-frequency filter 10I is connected to the surface of the antennasubstrate 991 which faces the front end substrate 990. The connector 612attached to the flat cable high-frequency filter 10I is connected to thesurface (mount surface) of the front end substrate 990 which faces theantenna substrate 991. Since the flat cable high-frequency filter 10Ihas flexibility, a curved or bent portion can be located somewherebetween the two ends of the flat cable high-frequency filter 10I in thelongitudinal direction. By providing a curved or bent portion, the flatcable high-frequency filter 10I is able to connect the front endsubstrate 990 and the antenna substrate 991 without being in contactwith the circuit components.

As described above, since a BPF is included in the flat cablehigh-frequency filter 10I, it is not necessary to provide a BPF in thefront end substrate 990 or the antenna substrate 991. Accordingly, thefront end substrate 990 and the antenna substrate 991 are reduced insize. By the provision of a BPF in the flat cable high-frequency filter10I, high filter characteristics (band pass characteristics andattenuation characteristics) of the BPF are obtained, thus improving thecommunication characteristics of the communication device module 900.

A flat cable high-frequency diplexer 90 according to a twelfth preferredembodiment will be described below with reference to the explodedperspective view of FIG. 27. In FIG. 27, protecting layers andconnectors are not shown.

The flat cable high-frequency diplexer 90 includes a dielectricsubstrate 20K constituted by dielectric layers 201K, 202K, 203K, and204K stacked on each other.

The dielectric substrate 201K includes partial regions 201K1, 201K2, and201K3. The partial regions 201K1 and 201K2 have an elongated shapeextending along the longitudinal direction and are disposed with a spacetherebetween in the widthwise direction. The partial region 201K3 isdisposed at one longitudinal end of each of the partial regions 201K1and 201K2, and connects the partial regions 201K1 and 201K2. With thisconfiguration, at a certain point between the two longitudinal ends ofthe dielectric layer 201K, the dielectric layer 201K is split into tworegions in the widthwise direction.

The dielectric substrate 202K includes partial regions 202K1, 202K2, and202K3. The partial regions 202K1 and 202K2 have an elongated shapeextending along the longitudinal direction and are disposed with a spacetherebetween in the widthwise direction. The partial region 202K3 isdisposed at one longitudinal end of each of the partial regions 202K1and 202K2, and connects the partial regions 202K1 and 202K2. With thisconfiguration, at a certain point between the two longitudinal ends ofthe dielectric layer 202K, the dielectric layer 202K is split into tworegions in the widthwise direction.

The dielectric substrate 203K includes partial regions 203K1, 203K2, and203K3. The partial regions 203K1 and 203K2 have an elongated shapeextending along the longitudinal direction and are disposed with a spacetherebetween in the widthwise direction. The partial region 203K3 isdisposed at one longitudinal end of each of the partial regions 203K1and 203K2, and connects the partial regions 203K1 and 203K2. With thisconfiguration, at a certain point between the two longitudinal ends ofthe dielectric layer 203K, the dielectric layer 203K is split into tworegions in the widthwise direction.

The dielectric substrate 204K includes partial regions 204K1, 204K2, and204K3. The partial regions 204K1 and 204K2 have an elongated shapeextending along the longitudinal direction and are disposed with a spacetherebetween in the widthwise direction. The partial region 204K3 isdisposed at one longitudinal end of each of the partial regions 204K1and 204K2, and connects the partial regions 204K1 and 204K2. With thisconfiguration, at a certain point between the two longitudinal ends ofthe dielectric layer 204K, the dielectric layer 204K is split into tworegions in the widthwise direction.

In a first substrate portion constituted by the partial regions 201K1,202K1, 203K1, and 204K1 of the dielectric substrate 20K, the sameconductor pattern as that of the ninth preferred embodiment is formed.Accordingly, in this first substrate portion, a BPF connected betweenextended conductors 441K and 442K is formed.

In the partial region 201K2 of the dielectric layer 201K, a loop shapedconductor pattern 601 is provided. The loop shaped conductor pattern 601includes linear first through fifth conductor patterns 6011 through6015.

The first conductor pattern 6011 extends in the widthwise direction ofthe partial region 201K2, and is located near the longitudinal endportion of the partial region 201K2 which is adjacent to the partialregion 201K3. The first conductor pattern 6011 is connected to theextended conductor 441K. The second conductor pattern 6012 extends inthe widthwise direction of the partial region 201K2, and is located nearthe longitudinal end portion of the partial region 201K2 which is spacedaway from the partial region 201K3. The second conductor pattern 6012 isconnected to an extended conductor 443K which is located near thelongitudinal end portion of the partial region 201K2 which is spacedaway from the partial region 201K3. The extended conductor 443K, as wellas the extended conductor 442K, is connected to, for example, aconnector, which is not shown.

The third conductor pattern 6013 extends in the longitudinal directionof the partial region 201K2, and is located near the widthwise endportion of the partial region 201K2 which is adjacent to the partialregion 201K1. The third conductor pattern 6013 is connected to the firstand second conductor patterns 6011 and 6012.

The fourth and fifth conductor patterns 6014 and 6015 extend in thelongitudinal direction of the partial region 201K2, and are formed nearthe widthwise end portion of the partial region 201K2 which is spacedaway from the partial region 201K1. The fourth and fifth conductorpatterns 6014 and 6015 are disposed along the longitudinal direction ofthe partial region 201K2 with a space therebetween. The fourth conductorpattern 6014 is connected to the first conductor pattern 6011, and thefifth conductor pattern 6015 is connected to the second conductorpattern 6012.

In the partial region 202K2 of the dielectric layer 202K, a loop shapedconductor pattern 602 is formed. The loop shaped conductor pattern 602includes linear first through fifth conductor patterns 6021 through6025.

The first conductor pattern 6021 extends in the widthwise direction ofthe partial region 202K2, and is located near the longitudinal endportion of the partial region 202K2 which is adjacent to the partialregion 202K3. The first conductor pattern 6021 is superposed on thefirst conductor pattern 6011, as viewed in the direction perpendicularto the principal surface of the dielectric substrate 20K. The secondconductor pattern 6022 extends in the widthwise direction of the partialregion 202K2, and is located near the longitudinal end portion of thepartial region 202K2 which is spaced away from the partial region 202K3.The second conductor pattern 6022 is superposed on the second conductorpattern 6012, as viewed in the direction perpendicular to the principalsurface of the dielectric substrate 20K. The third conductor pattern6023 extends in the longitudinal direction of the partial region 202K2,and is located near the widthwise end portion of the partial region202K2 which is adjacent to the partial region 202K1. The third conductorpattern 6023 is connected to the first and second conductor patterns6021 and 6022. The third conductor pattern 6023 is superposed on thethird conductor pattern 6013, as viewed in the direction perpendicularto the principal surface of the dielectric substrate 20K.

The fourth and fifth conductor patterns 6024 and 6025 extend in thelongitudinal direction of the partial region 202K2, and are located nearthe widthwise end portion of the partial region 202K2 which is spacedaway from the partial region 202K1. The fourth and fifth conductorpatterns 6024 and 6025 are disposed along the longitudinal direction ofthe partial region 202K2 with a space therebetween. The fourth conductorpattern 6024 is connected to the first conductor pattern 6021, and thefifth conductor pattern 6025 is connected to the second conductorpattern 6022. The fourth conductor pattern 6024 is superposed on thefourth conductor pattern 6014, as viewed in the direction perpendicularto the principal surface of the dielectric substrate 20K. The fifthconductor pattern 6025 is superposed on the fourth and fifth conductorpatterns 6014 and 6015, as viewed in the direction perpendicular to theprincipal surface of the dielectric substrate 20K.

In the partial region 203K2 of the dielectric layer 203K, a loop shapedconductor pattern 603 is formed. The loop shaped conductor pattern 603includes linear first through fifth conductor patterns 6031 through6035.

The first conductor pattern 6031 extends in the widthwise direction ofthe partial region 203K2, and is located near the longitudinal endportion of the partial region 203K2 which is adjacent to the partialregion 203K3. The first conductor pattern 6031 is superposed on thefirst conductor patterns 6011 and 6021, as viewed in the directionperpendicular to the principal surface of the dielectric substrate 20K.The second conductor pattern 6032 extends in the widthwise direction ofthe partial region 203K2, and is located near the longitudinal endportion of the partial region 203K2 which is spaced away from thepartial region 203K3. The second conductor pattern 6032 is superposed onthe second conductor patterns 6012 and 6022, as viewed in the directionperpendicular to the principal surface of the dielectric substrate 20K.The third conductor pattern 6033 extends in the longitudinal directionof the partial region 203K2, and is located near the widthwise endportion of the partial region 203K2 which is adjacent to the partialregion 203K1. The third conductor pattern 6033 is connected to the firstand second conductor patterns 6031 and 6032. The third conductor pattern6033 is superposed on the third conductor patterns 6013 and 6023, asviewed in the direction perpendicular to the principal surface of thedielectric substrate 20K.

The fourth and fifth conductor patterns 6034 and 6035 extend in thelongitudinal direction of the partial region 203K2, and are formed nearthe widthwise end portion of the partial region 203K2 which is spacedaway from the partial region 203K1. The fourth and fifth conductorpatterns 6034 and 6035 are disposed along the longitudinal direction ofthe partial region 203K2 with a space therebetween. The fourth conductorpattern 6034 is connected to the first conductor pattern 6031, and thefifth conductor pattern 6035 is connected to the second conductorpattern 6032. The fourth conductor pattern 6034 is superposed on thefourth and fifth conductor patterns 6024 and 6025, as viewed in thedirection perpendicular to the principal surface of the dielectricsubstrate 20K. The fifth conductor pattern 6035 is superposed on thefifth conductor pattern 6025, as viewed in the direction perpendicularto the principal surface of the dielectric substrate 20K.

In the partial region 204K2 of the dielectric layer 204K, a loop shapedconductor pattern 604 is provided. The loop shaped conductor pattern 604includes linear first through fifth conductor patterns 6041 through6045.

The first conductor pattern 6041 extends in the widthwise direction ofthe partial region 204K2, and is located near the longitudinal endportion of the partial region 204K2 which is adjacent to the partialregion 204K3. The first conductor pattern 6041 is superposed on thefirst conductor patterns 6011, 6021, and 6031, as viewed in thedirection perpendicular to the principal surface of the dielectricsubstrate 20K. The second conductor pattern 6042 extends in thewidthwise direction of the partial region 204K2, and is located near thelongitudinal end portion of the partial region 204K2 which is spacedaway from the partial region 204K3. The second conductor pattern 6042 issuperposed on the second conductor patterns 6012, 6022, and 6032, asviewed in the direction perpendicular to the principal surface of thedielectric substrate 20K. The third conductor pattern 6043 extends inthe longitudinal direction of the partial region 204K2, and is locatednear the widthwise end portion of the partial region 204K2 which isadjacent to the partial region 204K1. The third conductor pattern 6043is connected to the first and second conductor patterns 6041 and 6042.The third conductor pattern 6043 is superposed on the third conductorpatterns 6013, 6023, and 6033, as viewed in the direction perpendicularto the principal surface of the dielectric substrate 20K.

The fourth and fifth conductor patterns 6044 and 6045 extend in thelongitudinal direction of the partial region 204K2, and are located nearthe widthwise end portion of the partial region 204K2 which is spacedaway from the partial region 204K1. The fourth and fifth conductorpatterns 6044 and 6045 are disposed along the longitudinal direction ofthe partial region 204K2 with a space therebetween. The fourth conductorpattern 6044 is connected to the first conductor pattern 6041, and thefifth conductor pattern 6045 is connected to the second conductorpattern 6042. The fourth conductor pattern 6044 is superposed on thefourth conductor pattern 6034, as viewed in the direction perpendicularto the principal surface of the dielectric substrate 20K. The fifthconductor pattern 6045 is superposed on the fourth and fifth conductorpatterns 6034 and 6035, as viewed in the direction perpendicular to theprincipal surface of the dielectric substrate 20K.

The first conductor patterns 6011, 6021, 6031, and 6041 of thedielectric layers 201K, 202K, 203K, and 204K, respectively, areconnected to each other by a connecting conductor 60 extending in thethickness direction of the dielectric substrate 20K. The secondconductor patterns 6012, 6022, 6032, and 6042 of the dielectric layers201K, 202K, 203K, and 204K, respectively, are connected to each other bya connecting conductor 60 extending in the thickness direction of thedielectric substrate 20K. The third conductor patterns 6013, 6023, 6033,and 6043 of the dielectric layers 201K, 202K, 203K, and 204K,respectively, are connected to each other by a connecting conductor 60extending in the thickness direction of the dielectric substrate 20K.The fourth conductor patterns 6014, 6024, 6034, and 6044 of thedielectric layers 201K, 202K, 203K, and 204K, respectively, areconnected to each other by a connecting conductor 60 extending in thethickness direction of the dielectric substrate 20K. The fifth conductorpatterns 6015, 6025, 6035, and 6045 of the dielectric layers 201K, 202K,203K, and 204K, respectively, are connected to each other by aconnecting conductor 60 extending in the thickness direction of thedielectric substrate 20K.

With this configuration, the principal inductor is defined by the thirdconductor patterns 6013, 6023, 6033, and 6043. A region from the nodesbetween the first conductor patterns 6011, 6021, 6031, and 6041 and theextended conductor 441K to the end portions of the first conductorpatterns 6011, 6021, 6031, and 6041 connecting to the third conductorpatterns 6013, 6023, 6033, and 6043, respectively, and a region from thenodes between the second conductor patterns 6012, 6022, 6032, and 6042and the extended conductor 443K to the end portions of the secondconductor patterns 6012, 6022, 6032, and 6042 connecting to the thirdconductor patterns 6013, 6023, 6033, and 6043, respectively, also defineand function as inductors which continue from the principal inductorconstituted by the third conductor patterns 6013, 6023, 6033, and 6043.

A portion by which the fourth conductor pattern 6014 and the fifthconductor pattern 6025 oppose each other, a portion by which the fifthconductor pattern 6025 and the fourth conductor pattern 6034 oppose eachother, and a portion by which the fourth conductor pattern 6034 and thefifth conductor pattern 6045 oppose each other define and function ascapacitors.

With this configuration, a second substrate portion constituted by thepartial regions 201K2, 202K2, 203K2, and 204K2 of the dielectricsubstrate 20K defines a LC parallel resonance BEF including an inductorand a capacitor connected in parallel with each other. That is, a BEFconnected between the extended conductors 441K and 443K is provided inthe portion constituted by the partial regions 201K2, 202K2, 203K2, and204K2. In the above-described BPF, flat cable itself is a BPF. In asimilar manner, in the BEF, the flat cable itself is a BEF, thusexhibiting high band elimination characteristics (attenuationcharacteristics).

Then, by adjusting the elimination band (attenuation band) of the BEF tothe passband of the BPF, a high-frequency diplexer constituted by thedielectric substrate 20K on which the individual conductor patterns aredisposed is provided. It is thus possible to implement a thinhigh-frequency diplexer exhibiting high transmission characteristics.

The flat cable high-frequency diplexer 90 of the twelfth preferredembodiment may be used in a portion constituted by the BEF 921, the BPF922, and transmission lines to connect the BEF 921 and the BPF 922 tothe antenna 930, such as those shown in the circuit diagram of FIG. 25.

The flat cable high-frequency diplexer 90 of the twelfth preferredembodiment may also be used to connect the antenna substrate 991 and thefront end substrate 990 in a mounting mode, such as that shown in FIG.26.

A variable capacitance element may be attached to the above-describedflat cable high-frequency filters and the flat cable high-frequencydiplexer, so that it may be connected in series with the inductor andthe capacitor forming the above-described high-frequency filter. In thiscase, for example, a land conductor may be located at a position near anexternal connection conductor, and a mount variable capacitance elementmay be mounted on this land conductor.

While preferred embodiments of the present invention have been describedabove, it is to be understood that variations and modifications will beapparent to those skilled in the art without departing from the scopeand spirit of the present invention. The scope of the present invention,therefore, is to be determined solely by the following claims.

What is claimed is:
 1. A high-frequency filter connected between a firstcircuit element including an antenna and a second circuit element, thehigh-frequency filter comprising: a dielectric substrate that includes aflat film; a plurality of conductor patterns that are not connected toeach other and include a gap provided between opposing end portions ofthe plurality of conductor patterns; and a capacitive coupling conductorpattern that is superposed on the plurality of conductor patterns in athickness direction of the dielectric substrate through the dielectricsubstrate and is configured to capacitively couple the plurality ofconductor patterns, wherein the plurality of conductor patterns defineinductors; the capacitive coupling conductor pattern defines acapacitor; and a region of the dielectric substrate in which thecapacitive coupling conductor pattern is located is provided at aposition closer to the second circuit element than to the first circuitelement in the dielectric substrate.
 2. The high-frequency filteraccording to claim 1, further comprising a linear conductor provided inthe dielectric substrate between the first circuit element and theregion in which the capacitive coupling conductor pattern is located. 3.The high-frequency filter according to claim 1, wherein, in thedielectric substrate, a bent portion is located at a position other thanthe region in which the capacitive coupling conductor pattern islocated.
 4. The high-frequency filter according to claim 1, wherein thefirst circuit element and the second circuit element are located atdifferent positions in a height direction from each other; the firstcircuit element is connected to a first surface of the dielectricsubstrate; and the second circuit element is connected to a secondsurface of the dielectric substrate.
 5. The high-frequency filteraccording to claim 1, wherein the first circuit element and the secondcircuit element are connected through a connector provided on a surfaceof the dielectric substrate.
 6. The high-frequency filter according toclaim 1, wherein the second circuit element includes a substrate onwhich at least one of an integrated circuit (IC) chip and a mountcomponent is mounted.
 7. The high-frequency filter according to claim 1,wherein the dielectric substrate has a dielectric loss tangent equal toor smaller than about 0.005.
 8. The high-frequency filter according toclaim 7, wherein the dielectric substrate is made of a liquid crystalpolymer.
 9. The high-frequency filter according to claim 1, wherein thecapacitive coupling conductor pattern includes: a flat conductor patternwhich opposes a certain one of the plurality of conductor patterns witha dielectric layer of the dielectric substrate therebetween; and a flatregion of the certain one of the plurality of conductor patterns whichopposes the flat conductor pattern.
 10. The high-frequency filteraccording to claim 9, wherein a width of a conductor pattern whichopposes the capacitive coupling conductor pattern is the same orsubstantially the same as a width of a conductor pattern which does notoppose the capacitive coupling conductor pattern.
 11. The high-frequencyfilter according to claim 10, wherein the width of the conductorpatterns which opposes the capacitive coupling conductor pattern and thewidth of a conductor pattern which does not oppose the capacitivecoupling conductor pattern are the same or substantially the same as awidth of the dielectric substrate.
 12. An electronic device comprising:the high-frequency filter according to claim 1; and a plurality of mountcircuit members; wherein the plurality of mount circuit members areconnected to each other by the high-frequency filter.
 13. The electronicdevice according to claim 12, wherein the high-frequency filter isdisposed with a predetermined gap from each of the plurality of mountcircuit members.
 14. An electronic device comprising: a first circuitelement including an antenna; a second circuit element; and ahigh-frequency filter connected between the first circuit element andthe second circuit element, the high-frequency filter comprising: adielectric substrate that includes a flat film; a plurality of conductorpatterns that are not connected to each other and include a gap providedbetween opposing end portions of the plurality of conductor patterns;and a capacitive coupling conductor pattern that is superposed on theplurality of conductor patterns in a thickness direction of thedielectric substrate through the dielectric substrate and is configuredto capacitively couple the plurality of conductor patterns, wherein: theplurality of conductor patterns define inductors; the capacitivecoupling conductor pattern defines a capacitor; and a region of thedielectric substrate in which the capacitive coupling conductor patternis located is provided at a position closer to the second circuitelement than to the first circuit element in the dielectric substrate.15. The electronic device according to claim 14, further comprising alinear conductor provided in the dielectric substrate between the firstcircuit element and the region in which the capacitive couplingconductor pattern is located.
 16. The electronic device according toclaim 14, wherein, in the dielectric substrate, a bent portion islocated at a position other than the region in which the capacitivecoupling conductor pattern is located.
 17. The electronic deviceaccording to claim 14, wherein the first circuit element and the secondcircuit element are located at different positions in a height directionfrom each other; the first circuit element is connected to a firstsurface of the dielectric substrate; and the second circuit element isconnected to a second surface of the dielectric substrate.
 18. Theelectronic device according to claim 14, wherein the first circuitelement and the second circuit element are connected through a connectorprovided on a surface of the dielectric substrate.
 19. The electronicdevice according to claim 14, wherein the second circuit elementincludes a substrate on which at least one of an integrated circuit (IC)chip and a mount component is mounted.